package com.wk.demo.view;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.LinearLayout;
import android.widget.RadioButton;

public class XRadioGroup extends LinearLayout {
  // holds the checked id; the selection is empty by default
  private int mCheckedId = -1;
  // tracks children radio buttons checked state
  private CompoundButton.OnCheckedChangeListener mChildOnCheckedChangeListener;
  // when true, mOnCheckedChangeListener discards events
  private boolean mProtectFromCheckedChange = false;
  private OnCheckedChangeListener mOnCheckedChangeListener;
  private PassThroughHierarchyChangeListener mPassThroughListener;

  public XRadioGroup(Context context) {
    super(context);
    init();
  }

  public XRadioGroup(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  public XRadioGroup(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init();
  }

  @TargetApi(Build.VERSION_CODES.LOLLIPOP)
  public XRadioGroup(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
    init();
  }

  private void init() {
    mChildOnCheckedChangeListener = new CheckedStateTracker();
    mPassThroughListener = new PassThroughHierarchyChangeListener();
    super.setOnHierarchyChangeListener(mPassThroughListener);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
    // the user listener is delegated to our pass-through listener
    mPassThroughListener.mOnHierarchyChangeListener = listener;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected void onFinishInflate() {
    super.onFinishInflate();

    // checks the appropriate radio button as requested in the XML file
    if (mCheckedId != -1) {
      mProtectFromCheckedChange = true;
      setCheckedStateForView(mCheckedId, true);
      mProtectFromCheckedChange = false;
      setCheckedId(mCheckedId);
    }
  }

  private void setViewState(View child) {
    if (child instanceof RadioButton) {
      final RadioButton button = (RadioButton) child;
      if (button.isChecked()) {
        mProtectFromCheckedChange = true;
        if (mCheckedId != -1) {
          setCheckedStateForView(mCheckedId, false);
        }
        mProtectFromCheckedChange = false;
        setCheckedId(button.getId());
      }
    } else if (child instanceof ViewGroup) {
      ViewGroup view = (ViewGroup) child;
      for (int i = 0; i < view.getChildCount(); i++) {
        setViewState(view.getChildAt(i));
      }
    }
  }

  @Override
  public void addView(View child, int index, ViewGroup.LayoutParams params) {
    setViewState(child);
    super.addView(child, index, params);
  }

  /**
   * <p>Sets the selection to the radio button whose identifier is passed in
   * parameter. Using -1 as the selection identifier clears the selection;
   * such an operation is equivalent to invoking {@link #clearCheck()}.</p>
   *
   * @param id the unique id of the radio button to select in this group
   * @see #getCheckedRadioButtonId()
   * @see #clearCheck()
   */
  public void check(int id) {
    // don't even bother
    if (id != -1 && (id == mCheckedId)) {
      return;
    }

    if (mCheckedId != -1) {
      setCheckedStateForView(mCheckedId, false);
    }

    if (id != -1) {
      setCheckedStateForView(id, true);
    }

    setCheckedId(id);
  }

  private void setCheckedId(int id) {
    mCheckedId = id;
    if (mOnCheckedChangeListener != null) {
      mOnCheckedChangeListener.onCheckedChanged(this, mCheckedId);
    }
  }

  private void setCheckedStateForView(int viewId, boolean checked) {
    View checkedView = findViewById(viewId);
    if (checkedView != null && checkedView instanceof RadioButton) {
      ((RadioButton) checkedView).setChecked(checked);
    }
  }

  /**
   * <p>Returns the identifier of the selected radio button in this group.
   * Upon empty selection, the returned value is -1.</p>
   *
   * @return the unique id of the selected radio button in this group
   * @attr ref android.R.styleable#RadioGroup_checkedButton
   * @see #check(int)
   * @see #clearCheck()
   */
  public int getCheckedRadioButtonId() {
    return mCheckedId;
  }

  /**
   * <p>Clears the selection. When the selection is cleared, no radio button
   * in this group is selected and {@link #getCheckedRadioButtonId()} returns
   * null.</p>
   *
   * @see #check(int)
   * @see #getCheckedRadioButtonId()
   */
  public void clearCheck() {
    check(-1);
  }

  /**
   * <p>Register a callback to be invoked when the checked radio button
   * changes in this group.</p>
   *
   * @param listener the callback to call on checked state change
   */
  public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
    mOnCheckedChangeListener = listener;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public LayoutParams generateLayoutParams(AttributeSet attrs) {
    return new XRadioGroup.LayoutParams(getContext(), attrs);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
    return p instanceof XRadioGroup.LayoutParams;
  }

  @Override
  protected LinearLayout.LayoutParams generateDefaultLayoutParams() {
    return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
  }

  @Override
  public CharSequence getAccessibilityClassName() {
    return XRadioGroup.class.getName();
  }

  /**
   * <p>This set of layout parameters defaults the width and the height of
   * the children to {@link #WRAP_CONTENT} when they are not specified in the
   * XML file. Otherwise, this class ussed the value read from the XML file.</p>
   * <p/>
   * <p>See
   * {@link  LinearLayout Attributes}
   * for a list of all child view attributes that this class supports.</p>
   */
  public static class LayoutParams extends LinearLayout.LayoutParams {
    /**
     * {@inheritDoc}
     */
    public LayoutParams(Context c, AttributeSet attrs) {
      super(c, attrs);
    }

    /**
     * {@inheritDoc}
     */
    public LayoutParams(int w, int h) {
      super(w, h);
    }

    /**
     * {@inheritDoc}
     */
    public LayoutParams(int w, int h, float initWeight) {
      super(w, h, initWeight);
    }

    /**
     * {@inheritDoc}
     */
    public LayoutParams(ViewGroup.LayoutParams p) {
      super(p);
    }

    /**
     * {@inheritDoc}
     */
    public LayoutParams(MarginLayoutParams source) {
      super(source);
    }

    /**
     * <p>Fixes the child's width to
     * {@link ViewGroup.LayoutParams#WRAP_CONTENT} and the child's
     * height to  {@link ViewGroup.LayoutParams#WRAP_CONTENT}
     * when not specified in the XML file.</p>
     *
     * @param a the styled attributes set
     * @param widthAttr the width attribute to fetch
     * @param heightAttr the height attribute to fetch
     */
    @Override
    protected void setBaseAttributes(TypedArray a,
        int widthAttr, int heightAttr) {

      if (a.hasValue(widthAttr)) {
        width = a.getLayoutDimension(widthAttr, "layout_width");
      } else {
        width = WRAP_CONTENT;
      }

      if (a.hasValue(heightAttr)) {
        height = a.getLayoutDimension(heightAttr, "layout_height");
      } else {
        height = WRAP_CONTENT;
      }
    }
  }

  /**
   * <p>Interface definition for a callback to be invoked when the checked
   * radio button changed in this group.</p>
   */
  public interface OnCheckedChangeListener {
    /**
     * <p>Called when the checked radio button has changed. When the
     * selection is cleared, checkedId is -1.</p>
     *
     * @param group the group in which the checked radio button has changed
     * @param checkedId the unique identifier of the newly checked radio button
     */
    public void onCheckedChanged(XRadioGroup group, int checkedId);
  }

  private class CheckedStateTracker implements CompoundButton.OnCheckedChangeListener {
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
      // prevents from infinite recursion
      if (mProtectFromCheckedChange) {
        return;
      }

      mProtectFromCheckedChange = true;
      if (mCheckedId != -1) {
        setCheckedStateForView(mCheckedId, false);
      }
      mProtectFromCheckedChange = false;

      int id = buttonView.getId();
      setCheckedId(id);
    }
  }

  /**
   * <p>A pass-through listener acts upon the events and dispatches them
   * to another listener. This allows the table layout to set its own internal
   * hierarchy change listener without preventing the user to setup his.</p>
   */
  private class PassThroughHierarchyChangeListener implements
      OnHierarchyChangeListener {
    private OnHierarchyChangeListener mOnHierarchyChangeListener;

    /**
     * {@inheritDoc}
     */
    public void onChildViewAdded(View parent, View child) {
      setListener(child);

      if (mOnHierarchyChangeListener != null) {
        mOnHierarchyChangeListener.onChildViewAdded(parent, child);
      }
    }

    /**
     * {@inheritDoc}
     */
    public void onChildViewRemoved(View parent, View child) {
      removeListener(child);

      if (mOnHierarchyChangeListener != null) {
        mOnHierarchyChangeListener.onChildViewRemoved(parent, child);
      }
    }
  }

  /**
   * 设置监听
   */
  private void setListener(View child) {
    if (child instanceof RadioButton) {
      int id = child.getId();
      // generates an id if it's missing
      if (id == View.NO_ID) {
        id = child.hashCode();
        child.setId(id);
      }
      ((RadioButton) child).setOnCheckedChangeListener(
          mChildOnCheckedChangeListener);
    } else if (child instanceof ViewGroup) {
      ViewGroup view = (ViewGroup) child;
      for (int i = 0; i < view.getChildCount(); i++) {
        setListener(view.getChildAt(i));
      }
    }
  }

  /**
   * 移除监听
   */
  private void removeListener(View child) {
    if (child instanceof RadioButton) {
      ((RadioButton) child).setOnCheckedChangeListener(null);
    } else if (child instanceof ViewGroup) {
      ViewGroup view = (ViewGroup) child;
      for (int i = 0; i < view.getChildCount(); i++) {
        removeListener(view.getChildAt(i));
      }
    }
  }
}